diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index e6024a980bb..0a8bac25f59 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -490,9 +490,6 @@ heapgetpage(TableScanDesc sscan, BlockNumber block)
  *		tuple as indicated by "dir"; return the next tuple in scan->rs_ctup,
  *		or set scan->rs_ctup.t_data = NULL if no more tuples.
  *
- * dir == NoMovementScanDirection means "re-fetch the tuple indicated
- * by scan->rs_ctup".
- *
  * Note: the reason nkeys/key are passed separately, even though they are
  * kept in the scan descriptor, is that the caller may not want us to check
  * the scankeys.
@@ -583,7 +580,7 @@ heapgettup(HeapScanDesc scan,
 
 		linesleft = lines - lineoff + 1;
 	}
-	else if (backward)
+	else
 	{
 		/* backward parallel scan not supported */
 		Assert(scan->rs_base.rs_parallel == NULL);
@@ -653,34 +650,6 @@ heapgettup(HeapScanDesc scan,
 
 		linesleft = lineoff;
 	}
-	else
-	{
-		/*
-		 * ``no movement'' scan direction: refetch prior tuple
-		 */
-		if (!scan->rs_inited)
-		{
-			Assert(!BufferIsValid(scan->rs_cbuf));
-			tuple->t_data = NULL;
-			return;
-		}
-
-		block = ItemPointerGetBlockNumber(&(tuple->t_self));
-		if (block != scan->rs_cblock)
-			heapgetpage((TableScanDesc) scan, block);
-
-		/* Since the tuple was previously fetched, needn't lock page here */
-		page = BufferGetPage(scan->rs_cbuf);
-		TestForOldSnapshot(snapshot, scan->rs_base.rs_rd, page);
-		lineoff = ItemPointerGetOffsetNumber(&(tuple->t_self));
-		lpp = PageGetItemId(page, lineoff);
-		Assert(ItemIdIsNormal(lpp));
-
-		tuple->t_data = (HeapTupleHeader) PageGetItem(page, lpp);
-		tuple->t_len = ItemIdGetLength(lpp);
-
-		return;
-	}
 
 	/*
 	 * advance the scan until we find a qualifying tuple or run out of stuff
@@ -918,7 +887,7 @@ heapgettup_pagemode(HeapScanDesc scan,
 
 		linesleft = lines - lineindex;
 	}
-	else if (backward)
+	else
 	{
 		/* backward parallel scan not supported */
 		Assert(scan->rs_base.rs_parallel == NULL);
@@ -978,38 +947,6 @@ heapgettup_pagemode(HeapScanDesc scan,
 
 		linesleft = lineindex + 1;
 	}
-	else
-	{
-		/*
-		 * ``no movement'' scan direction: refetch prior tuple
-		 */
-		if (!scan->rs_inited)
-		{
-			Assert(!BufferIsValid(scan->rs_cbuf));
-			tuple->t_data = NULL;
-			return;
-		}
-
-		block = ItemPointerGetBlockNumber(&(tuple->t_self));
-		if (block != scan->rs_cblock)
-			heapgetpage((TableScanDesc) scan, block);
-
-		/* Since the tuple was previously fetched, needn't lock page here */
-		page = BufferGetPage(scan->rs_cbuf);
-		TestForOldSnapshot(scan->rs_base.rs_snapshot, scan->rs_base.rs_rd, page);
-		lineoff = ItemPointerGetOffsetNumber(&(tuple->t_self));
-		lpp = PageGetItemId(page, lineoff);
-		Assert(ItemIdIsNormal(lpp));
-
-		tuple->t_data = (HeapTupleHeader) PageGetItem(page, lpp);
-		tuple->t_len = ItemIdGetLength(lpp);
-
-		/* check that rs_cindex is in sync */
-		Assert(scan->rs_cindex < scan->rs_ntuples);
-		Assert(lineoff == scan->rs_vistuples[scan->rs_cindex]);
-
-		return;
-	}
 
 	/*
 	 * advance the scan until we find a qualifying tuple or run out of stuff
diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index 35c23bd27df..fbbf28cf063 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -3746,9 +3746,6 @@ ExplainIndexScanDetails(Oid indexid, ScanDirection indexorderdir,
 			case BackwardScanDirection:
 				scandir = "Backward";
 				break;
-			case NoMovementScanDirection:
-				scandir = "NoMovement";
-				break;
 			case ForwardScanDirection:
 				scandir = "Forward";
 				break;
diff --git a/src/backend/executor/nodeIndexonlyscan.c b/src/backend/executor/nodeIndexonlyscan.c
index 8c7da9ee60a..0b43a9b9699 100644
--- a/src/backend/executor/nodeIndexonlyscan.c
+++ b/src/backend/executor/nodeIndexonlyscan.c
@@ -70,15 +70,13 @@ IndexOnlyNext(IndexOnlyScanState *node)
 	 * extract necessary information from index scan node
 	 */
 	estate = node->ss.ps.state;
-	direction = estate->es_direction;
-	/* flip direction if this is an overall backward scan */
-	if (ScanDirectionIsBackward(((IndexOnlyScan *) node->ss.ps.plan)->indexorderdir))
-	{
-		if (ScanDirectionIsForward(direction))
-			direction = BackwardScanDirection;
-		else if (ScanDirectionIsBackward(direction))
-			direction = ForwardScanDirection;
-	}
+
+	/*
+	 * Determine which direction to scan the index in based on the plan's scan
+	 * direction and the current direction of execution.
+	 */
+	direction = ScanDirectionCombine(estate->es_direction,
+									 ((IndexOnlyScan *) node->ss.ps.plan)->indexorderdir);
 	scandesc = node->ioss_ScanDesc;
 	econtext = node->ss.ps.ps_ExprContext;
 	slot = node->ss.ss_ScanTupleSlot;
diff --git a/src/backend/executor/nodeIndexscan.c b/src/backend/executor/nodeIndexscan.c
index f1ced9ff0fa..4540c7781d2 100644
--- a/src/backend/executor/nodeIndexscan.c
+++ b/src/backend/executor/nodeIndexscan.c
@@ -90,15 +90,13 @@ IndexNext(IndexScanState *node)
 	 * extract necessary information from index scan node
 	 */
 	estate = node->ss.ps.state;
-	direction = estate->es_direction;
-	/* flip direction if this is an overall backward scan */
-	if (ScanDirectionIsBackward(((IndexScan *) node->ss.ps.plan)->indexorderdir))
-	{
-		if (ScanDirectionIsForward(direction))
-			direction = BackwardScanDirection;
-		else if (ScanDirectionIsBackward(direction))
-			direction = ForwardScanDirection;
-	}
+
+	/*
+	 * Determine which direction to scan the index in based on the plan's scan
+	 * direction and the current direction of execution.
+	 */
+	direction = ScanDirectionCombine(estate->es_direction,
+									 ((IndexScan *) node->ss.ps.plan)->indexorderdir);
 	scandesc = node->iss_ScanDesc;
 	econtext = node->ss.ps.ps_ExprContext;
 	slot = node->ss.ss_ScanTupleSlot;
diff --git a/src/backend/optimizer/path/indxpath.c b/src/backend/optimizer/path/indxpath.c
index e9b784bcab9..721a0752018 100644
--- a/src/backend/optimizer/path/indxpath.c
+++ b/src/backend/optimizer/path/indxpath.c
@@ -1015,9 +1015,7 @@ build_index_paths(PlannerInfo *root, RelOptInfo *rel,
 								  orderbyclauses,
 								  orderbyclausecols,
 								  useful_pathkeys,
-								  index_is_ordered ?
-								  ForwardScanDirection :
-								  NoMovementScanDirection,
+								  ForwardScanDirection,
 								  index_only_scan,
 								  outer_relids,
 								  loop_count,
@@ -1037,9 +1035,7 @@ build_index_paths(PlannerInfo *root, RelOptInfo *rel,
 									  orderbyclauses,
 									  orderbyclausecols,
 									  useful_pathkeys,
-									  index_is_ordered ?
-									  ForwardScanDirection :
-									  NoMovementScanDirection,
+									  ForwardScanDirection,
 									  index_only_scan,
 									  outer_relids,
 									  loop_count,
diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c
index 1b118528141..134130476e4 100644
--- a/src/backend/optimizer/plan/createplan.c
+++ b/src/backend/optimizer/plan/createplan.c
@@ -3017,6 +3017,9 @@ create_indexscan_plan(PlannerInfo *root,
 	/* it should be a base rel... */
 	Assert(baserelid > 0);
 	Assert(best_path->path.parent->rtekind == RTE_RELATION);
+	/* check the scan direction is valid */
+	Assert(best_path->indexscandir == ForwardScanDirection ||
+		   best_path->indexscandir == BackwardScanDirection);
 
 	/*
 	 * Extract the index qual expressions (stripped of RestrictInfos) from the
diff --git a/src/backend/optimizer/util/pathnode.c b/src/backend/optimizer/util/pathnode.c
index f2bf68d33be..d749b505785 100644
--- a/src/backend/optimizer/util/pathnode.c
+++ b/src/backend/optimizer/util/pathnode.c
@@ -982,9 +982,7 @@ create_samplescan_path(PlannerInfo *root, RelOptInfo *rel, Relids required_outer
  * 'indexorderbycols' is an integer list of index column numbers (zero based)
  *			the ordering operators can be used with.
  * 'pathkeys' describes the ordering of the path.
- * 'indexscandir' is ForwardScanDirection or BackwardScanDirection
- *			for an ordered index, or NoMovementScanDirection for
- *			an unordered index.
+ * 'indexscandir' is either ForwardScanDirection or BackwardScanDirection.
  * 'indexonly' is true if an index-only scan is wanted.
  * 'required_outer' is the set of outer relids for a parameterized path.
  * 'loop_count' is the number of repetitions of the indexscan to factor into
diff --git a/src/include/access/sdir.h b/src/include/access/sdir.h
index 16cb06c709b..322aeb3ff9d 100644
--- a/src/include/access/sdir.h
+++ b/src/include/access/sdir.h
@@ -16,8 +16,10 @@
 
 
 /*
- * ScanDirection was an int8 for no apparent reason. I kept the original
- * values because I'm not sure if I'll break anything otherwise.  -ay 2/95
+ * Defines the direction for scanning a table or an index.  Scans are never
+ * invoked using NoMovementScanDirectionScans.  For convenience, we use the
+ * values -1 and 1 for backward and forward scans.  This allows us to perform
+ * a few mathematical tricks such as what is done in ScanDirectionCombine.
  */
 typedef enum ScanDirection
 {
@@ -26,6 +28,13 @@ typedef enum ScanDirection
 	ForwardScanDirection = 1
 } ScanDirection;
 
+/*
+ * Determine the net effect of two direction specifications.
+ * This relies on having ForwardScanDirection = +1, BackwardScanDirection = -1,
+ * and will probably not do what you want if applied to any other values.
+ */
+#define ScanDirectionCombine(a, b)  ((a) * (b))
+
 /*
  * ScanDirectionIsValid
  *		True iff scan direction is valid.
diff --git a/src/include/access/tableam.h b/src/include/access/tableam.h
index 3fb184717f6..652e96f1b0b 100644
--- a/src/include/access/tableam.h
+++ b/src/include/access/tableam.h
@@ -1035,6 +1035,10 @@ table_scan_getnextslot(TableScanDesc sscan, ScanDirection direction, TupleTableS
 {
 	slot->tts_tableOid = RelationGetRelid(sscan->rs_rd);
 
+	/* We don't expect actual scans using NoMovementScanDirection */
+	Assert(direction == ForwardScanDirection ||
+		   direction == BackwardScanDirection);
+
 	/*
 	 * We don't expect direct calls to table_scan_getnextslot with valid
 	 * CheckXidAlive for catalog or regular tables.  See detailed comments in
@@ -1099,6 +1103,10 @@ table_scan_getnextslot_tidrange(TableScanDesc sscan, ScanDirection direction,
 	/* Ensure table_beginscan_tidrange() was used. */
 	Assert((sscan->rs_flags & SO_TYPE_TIDRANGESCAN) != 0);
 
+	/* We don't expect actual scans using NoMovementScanDirection */
+	Assert(direction == ForwardScanDirection ||
+		   direction == BackwardScanDirection);
+
 	return sscan->rs_rd->rd_tableam->scan_getnextslot_tidrange(sscan,
 															   direction,
 															   slot);
diff --git a/src/include/nodes/pathnodes.h b/src/include/nodes/pathnodes.h
index 62d9460258c..0d4b1ec4e42 100644
--- a/src/include/nodes/pathnodes.h
+++ b/src/include/nodes/pathnodes.h
@@ -1672,12 +1672,9 @@ typedef struct Path
  * on which index column each ORDER BY can be used with.)
  *
  * 'indexscandir' is one of:
- *		ForwardScanDirection: forward scan of an ordered index
+ *		ForwardScanDirection: forward scan of an index
  *		BackwardScanDirection: backward scan of an ordered index
- *		NoMovementScanDirection: scan of an unordered index, or don't care
- * (The executor doesn't care whether it gets ForwardScanDirection or
- * NoMovementScanDirection for an indexscan, but the planner wants to
- * distinguish ordered from unordered indexes for building pathkeys.)
+ * Unordered indexes will always have an indexscandir of ForwardScanDirection.
  *
  * 'indextotalcost' and 'indexselectivity' are saved in the IndexPath so that
  * we need not recompute them when considering using the same index in a